Intraluminal pressure triggers a rapid and persistent reinforcement of endothelial barriers

In response to mechanical cues, endothelial cells elicit highly sensitive cellular response pathways that contribute to the regulation of the physiology and disorders of the vascular system. However, it remains relatively unexplored how endothelial tissues process and integrate the intraluminal pressure, and in turn regulate the permeation flow across the vessel wall. Leveraging a tissue engineering approach to create microvessels (MVs), we measured real-time permeation flow induced by intraluminal pressures ranging from 0.1 to 2.0 kPa. Our findings reveal that mechanically stimulated MVs strengthen their barrier function within seconds of exposure to pressures below 1 kPa, with this enhanced barrier function persisting for 30 minutes. We demonstrate that this barrier reinforcement is linked to the closure of paracellular gaps. Additionally, we observe that it is associated with, and depends on, actin cytoskeleton reorganization, including the accumulation of stress fibers near intercellular junctions and the broadening of adherence junction protein localization. These findings provide insights into the ability of endothelial tissues to regulate interstitial fluid flow in response to sudden increases in blood pressure.